Astronomy and Astrophysics – Astrophysics
Scientific paper
Jun 1995
adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=1995a%26a...298..869m&link_type=abstract
Astronomy and Astrophysics, v.298, p.869
Astronomy and Astrophysics
Astrophysics
12
Stars: Circumstellar Matter, Stars: Late Type, Line: Formation, Stars: Mass Loss, Scattering
Scientific paper
We present new scattering measurements of KI or NaI in circumstellar envelopes, with the discovery of emissions around β Peg (M2.5II-III), ρ Per (M4IIb-IIIa) and CE Tau (M2Iab-Ib), expanding on previous detections to very low mass-loss rates (10^-9^Msun_/yr). Supplementary data for α Ori and μ Cep, and upper limits for TX Psc, Y CVn, ρ Cas and BU Gem are also given. We homogeneously reanalysed the line surface brightnesses of the envelopes in order to consider the NaI λ5896/KI λ7699 line ratio. This ratio is found to be around 3, within a factor of 2, for the envelopes of μ Cep, α Her and o Ceti. It is considerably different for α Ori, in the sense that NaI is about 80 times too faint. CE Tau also seems to display a similar effect. Our analysis suggests that NaI interstellar absorption on the line of sight of Betelgeuse is the simplest explanation, though not completely convincing. Despite its location in the galactic plane, the NaI-emitting shell around μ Cep would not be so strongly affected by interstellar NaI owing to a favourable Doppler shift. If the Betelgeuse NaI faintness is due to such an interstellar mutilation (and possibly also to inhomogeneities in the envelopes and measurement errors), our observations strengthen the evidence for a low condensation of K and Na in oxygen-rich envelopes with moderate mass-loss rates (up to ~2-4x10^-6^Msun_/yr). We briefly examine other possible, although less probable, explanations like some Na overabundance on μ Cep, or Na versus K differentiation, as found in comets.
Guilain Ch.
Mauron Nicolas
No associations
LandOfFree
NaI and KI scattering in circumstellar envelopes: new detections around giants and the NaI λ5896/KI λ7699 line ratio. does not yet have a rating. At this time, there are no reviews or comments for this scientific paper.
If you have personal experience with NaI and KI scattering in circumstellar envelopes: new detections around giants and the NaI λ5896/KI λ7699 line ratio., we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and NaI and KI scattering in circumstellar envelopes: new detections around giants and the NaI λ5896/KI λ7699 line ratio. will most certainly appreciate the feedback.
Profile ID: LFWR-SCP-O-1201256